Rare earth luminescent materials have excellent energy conversion function and exhibit superior luminescent properties because of their unique electronic shell structure, and currently they have become important photoelectric functional materials. The rare earth luminescent materials are widely used in high-definition display such as cathode ray tubes (CRT), plasma display panels (PDP), field emission devices (FED) and the like. Wherein FED is a low-voltage and high-current device, in recent years, it has received much concern due to its advantages of low operating voltage, low power consumption, no deflection coil, X-ray radiation free, anti-radiation and magnetic interference and the like. A field emission light source with high brightness, high quality of color rendering may be obtained by using a luminescent material excited by field emission cathode ray, and the field emission light source may be applied to the fields of professional lighting, display, signal indication as well as ordinary lighting and the like.
Currently, most of the luminescent materials for FED are made on the base of conventional phosphor powder for CRT, such as ZnS:Ag,Cl, SrGa2S4:Ce, SrGa2S4:Eu, Y2O2S:Eu, Y2SiO5:Ce, ZnGa2O4:Mn, Y2SiO5:Eu and Y2O3:Eu or the like, and some improvement has been made thereto. However, the working condition of the FED and that of the CRT are different, wherein the working voltage of CRT is high, is 15-30 kV, and the working voltage of FED is relatively lower, is generally below 10 kV. In order to obtain the potential advantages in the aspects of brightness, response time, working temperature range, energy consumption and the like, a series of conditions such as the brightness, luminous color, conductivity, stability, lifetime and luminous efficiency and the like of the phosphor powder for FED are required. And the exiting sulfide, oxysulfide and oxide phosphors have some deficiencies, although the phosphor powder containing sulfur has a high brightness, the stability thereof is poor; although the oxide has good stability, the luminous brightness thereof is not as good as sulfide.